The invention relates to a high density multichip module packaging structure.
A multichip module has been known as a valid structure for packaging a plurality of integrated circuit chips such as LSI chips on a single substrate for improvement in a packaging density. Various types of the high density packaging structures have already been developed. One of the conventional packaging structures will be described with reference to FIG. 1. A plurality of LSI chips 19 are mounted through bumps 18 or bonding wires 20 on a multichip module substrate 21. The multichip module substrate 21 is provided thereon with frames 24 surrounding a mounting region on which the plural LSI chips 19 are mounted. A space surrounding by the frames 24 provided on the multichip module substrate 21, wherein the space includes the plural LSI chips 19, is filled with a sealing resin 25 within which the LSI chips 19 are buried for sealing. The multichip module substrate 21 is mounted through bumps 23 on a mother board 22.
Another type of conventional packaging structure is illustrated in FIGS. 2A :and 2B wherein a mother board, on which a multichip module substrate is mounted, is not illustrated. A plurality of LSI chips 29 are mounted through bumps or bonding wires 20 on a multichip module substrate 30. The multichip module substrate 30 is provided thereon with frames 28 surrounding a mounting region on which the plural LSI chips 29 are mounted. A space surrounding by the frames 28 provided on the multichip module substrate 30, wherein the space includes the plural LSI chips 29, is filled with a sealing resin 25 within which the LSI chips 29 are buried for sealing. The multichip module substrate 30 is mounted through bumps which are not illustrated on a mother board which is also not illustrated. The multichip module substrate 30 is further provided at its side face with terminals 27. The terminals 27 are provided to surround the side faces of the multichip module substrate 30.
Recently, the requirement for improvement in the high density packaging of the multichip modules has escalated increasingly. So it is required to further improve a packaging density of the multichip module. In the above described packaging structure, a bottom surface of the multichip module substrate is used only to provide a bonding surface on the mother board, for that reason it is impossible to provide any integrated circuit chips or any elements on both the top and bottom surfaces to obtain a further improvement of the packaging density. Under the above circumstances, it is required to develop a novel packaging structure for multichip modules to allow a considerable improvement in a packaging density thereof.